Arc-lamp electrode.



FRANK R. CRANE, an, OF CHICAGO,

JAMPOLI$ AND ONE-THIRD T0 GEORGE N.

ILLINOIS, ASSIGNOR OF ONE-THIRD TO HENRY NELSON, BO'II-I OF CHICAGO, ILLINOIS.

' ARC-LAMP ELECTRODE.

No Drawing.

Specification of Letters Patent.

Patented Oct. 1a, was.

Application filed March 31, 1913. Serial No. 758,025.

To all whom it may concern Be it known that I, FRANK R. CRANE, Jr., a citizen of the United States, residing at Chicago, county of Cook, and State of Illinois, have invented a new and useful Improvement in Arc Lamp Electrodes, of which the following is a specification.

My invention relates to are lamp electrodes and contemplates better and more efficient composition which will produce more desirable light. There are a great many electrodes on the market of various compositions which burn with a flaming are but such electrodes contain too much sodium and the light is sickly and trying on the eyes.-

My improved electrodes will cause a flaming are but the light is of whitish pink color and much softer and less trying on the eyes. The greater part of the electrode is of some carbonaceous substance which will give sufficient conductivity to current flow. With this conducting material are mixed various substances to give the desired color and intensity of light, and a suitable binder is added, the entire mass being compressed into form and may be baked.

I preferably use comminuted carbon orlamp black as the conducting body and add thereto soda ash, cast iron filings, metallic magnesium in suitable proportions to give the desired color and intensity, and preferably use cla-y as a binder. The mixture is compressed and dried and, if desired, may be baked.

When the electrodes are connected in circuit and an are forms between them the substance added to the carbon will fuse and when the circuit is brokenthis fused mass cools and becomes glassy. The proportion of carbon should be large enough so that the glassy mass will retain sufiicient carbon to enable current flow therethrough to start the are when the circuit is again closed.

Lfind that the following proportions give very eflicient results:

Comminuted carbon or lamp black 7 5.

Soda ash 12.5%

Cast iron filings 5. Metallic Magnesium 5.

Binder such as clay 2.5%

The soda ash, filings ,and magnesium combine to give a soft whitish pink light which has considerable volume but which does not try or hurt the eyes. The light closely resembles day light and is therefore much more desirable than the sickly yellow light given off by other electrodes.

It is evident that the proportions above may be somewhat varied without decreasing the efficiency and I do not therefore desire to be limited to the exact proportions stated.

I claim the following:

1. An electrode composed of a mixture of about 7 5% comminuted carbon, 12.5% soda ash, 5% iron filings, 5% metallic magnesium, and the remainder a suitable binder.

2. An electrode composed of the ingredients Comminuted carbon or lamp black" 75. I

Soda ash 12.5% Cast iron filings--. 5. Metallic magnesium 5.

Clay as a binder 2.5%

FRANK R. CRANE, JR.

Witnesses:

BENJ. S. MESIROW, Enw. R. NEUMANN.

the presence 

